BOOK_CONTENT
From The Geometrical Tolerancing Desk Reference: Creating and Interpreting ISO Standard Technical Drawings

Overview

Maximum material condition (MMC) is the condition when a component or feature of a component has the maximum amount of material.

Example 1

For a shaft, MMC would be when the diameter is everywhere at its maximum size.

For a hole, MMC is when its diameter is everywhere at its minimum size.

Table 12.1: MMC related definitions

Definition

Abbreviation

Meaning

Maximum material condition

MMC

The state of a feature where the feature is everywhere at its maximum material

Maximum material size

MMS

The limit of size where the material of a feature is at its maximum. Shaft - maximum limit of size Hole - minimum limit of size

Maximum material virtual size

MMVS

The maximum material size plus or minus the geometrical tolerance. (for a shaft) MMVS=MMS + geometrical tolerance (for a hole) MMVS=MMS - geometrical tolerance

Maximum material requirement

MMR

When MMR is required on a drawing it is indicated on the drawing by placing the symbol in the tolerance frame either after the geometrical tolerance, after the datum letter or both

The symbol can be placed in the tolerance frame in the following ways:

Maximum Material Principle

The maximum material principle applies only to features with an AXIS or MEDIAN PLANE.


Figure 12.1: Example of applying maximum material principle

The actual measured diameter of the pin (figure 12.1) depicts the total increase in straightness tolerance. If the actual pin is 20 the allowed straightness tolerance is 0.1 but if the actual pin is 19.96 then...

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Topics of Interest

Chapter List Chapter 19: Geometrical Tolerancing Examples Overview Note The tolerance value used in the tolerance frame of the examples in section 19 are not standard values and are used purely...

11.1 Definitions Least material condition (LMC) The state of the considered feature in which the feature is everywhere at that limit of size where the material of the feature is at its minimum, e.g.

AVG average BASIC theoretical exact dimension CMM coordinate measuring machine DIA diameter D&T dimensioning and tolerancing FIM full indicator movement FIR full indicator reading FRTZF...

9.1 Definitions Actual local size (two-point size) Any individual distance at any cross-section of a feature of size (see p. xviii), i.e. any size measured between any two opposite points (twopoint...

Geometrical tolerances are placed in a rectangular frame in various forms as shown below: Example 1: Without datum Example 2: With datum Example 3: With multiple datum references Example 4: With MMR...